AV_PIX_FMT_MONOBLACK has the AV_PIX_FMT_FLAG_BITSTREAM flag, i.e.
linesize can be smaller than width.
Since x_offset is only check against the width, this can lead to
x_offset * bpp >= image_linesize.
In this case ptr could be set to a position outside the image_buf in
png_handle_row, leading to memory corruption and thus crashes.
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
} else if ((s->bits_per_pixel == 1 || s->bits_per_pixel == 2 || s->bits_per_pixel == 4 || s->bits_per_pixel == 8) &&
s->color_type == PNG_COLOR_TYPE_PALETTE) {
avctx->pix_fmt = AV_PIX_FMT_PAL8;
- } else if (s->bit_depth == 1 && s->bits_per_pixel == 1) {
+ } else if (s->bit_depth == 1 && s->bits_per_pixel == 1 && avctx->codec_id != AV_CODEC_ID_APNG) {
avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
} else if (s->bit_depth == 8 &&
s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {